Manage your subscription

It’s a Dog’s Life: Most of the 500 dog breeds round the world are affected by at least one genetic disease; how DNA mapping might help

By
JOHN BONNER in
SCIENCE WRITER, LONDON

AS PUPPIES, the dogs seemed no different from their litter mates. The
disease developed insidiously. By the age of two their night sight had
deteriorated, and by middle age they were completely blind. The cruel irony
was that these dogs were Labrador retrievers bred to become guide dogs for the
blind.

The animals had inherited a disease called progressive retinal atrophy
(PRA) which afflicted many of the animals trained by the Guide Dogs for the
Blind Association during the 1970s and 1980s. Screening young dogs for early
signs of the disease has prevented new cases developing in the past five
years. But the condition could return if new dogs are brought in for breeding
purposes. This potential threat, along with past experience, persuaded the
charity to fund a research project at the Animal Health Trust (AHT),
Newmarket. The aim of the project, which was set up in 1991, was to help to
eradicate PRA and many of the 300 genetic diseases which affect pedigree dogs.
A similar project was being funded in the US by the American Kennel Club.

Working with colleagues at the University of Leicester and several research
institutes such as University of California at Berkeley and the University of
Michigan in the US, the British scientists are mapping the DNA of the dog.
When the map is complete, it will enable scientists to develop diagnostic
tests for conditions like PRA which are caused by a mutation in a single gene,
and may eventually lead to treatments for hereditary diseases in dogs, and
could help researchers investigating the genetic basis of …